Heat exchange apparatus



Nov.v 3, 1942; M. `l-:T-rlNcs'roN ET AL HEAT EXCHANGE APPARATUS Filed Feb. 25, 1941 '3 Sheets-Sheet 1 NOV. 3, 1942- M. ETTlNGToN ETAL 2,301,113

HEAT EXCHANG APPARATUS Filed Feb. 25, 1941 5 Sheets-Sheet 2 RNEY Nov. 3, 1942. M. ETTINGTON Erm. 2,301,113

HEAT EXCHANGE APPARATUS I Filed Feb. 25, 1941, s sheeis-sneet s s m /r x. www. mw @JB n n T me O mU L| ww um uw m n u EN@ kw .imm A my l- W.@ l .nu .mmf B l- @.9 X- I ,l IH A .JLM L .WN NN S QN .Q ww `QN\ "ON 1 "QN /ll'llllIlIL arc/a7 A RNEY Patented Nov. 3, 1942 UNITED STATELS FATENT YOFFICE HEAT EXCHANGE APPARATUS Martin Ettington, Pelham, and -John MacRae Barclay, Brooklyn, N. Y., assignors to American Locomotive Company, New York, N. Y., a corporation of New York application February 25, 1941, serial No. 380,497

(o1. 2st- 24m 1 Claim.

I of the other fluid.

An object of the invention is to employ, in va heat exchanger of the foregoing type, separate return bends for interconnecting tubes instead of the tube sheets usually employed for inter connecting tubes, the sheets having been found unsatisfactory due to their tendency'to distort and creep, especially in the case of relatively thick sheets required in high temperature and pressure heat exchangers.

Another object is to provide, in an exchanger of the just mentioned characteristics, a system of bailles, associated with theI tubes, insuring circuitous or winding passage of the uid in the shell in one direction and return in the opposite direction, thereby providing ample heat transfer relation thereof with the fluid in the tubes.

A further object is to mount the tubes in association with the baffles and shell to allow free expansion of the tubes in both directions relative to the shell and bailles.

Other and further objects of this invention will appear from the following description, the ac.- companying drawings and the appended claim.

Referring to the drawings forming part of this application, Figure 1 is a sectional view of the heat exchanger involving the present invention, taken on the line I--I of Fig. 2, being broken away 'through the central portion and contracted to save space, parts being shown in full and other parts omitted, and a terminal coupling being shown partly in section; Fig. 2 is a sectional vview of the heat exchanger taken on the line IL-II of Fig. 1; Fig. 3 is a section on the line III-III of Fig. 5, showing the tubes fragmentally; Fig. 4 is an enlarged sectional view of the heat exchanger taken on the line IV-IV. of Fig. 1, parts being shown in full; Fig. 5 is a section on the line V--V of Fig. 1, enlarged similar to Fig. Ll; Fig. 6 is a plan of a unitary transverse 'baille assemblage shown partly in section, and the shell indicated in dot and dash lines, the assemblage and shell being broken away similar to Fig. 1; Figs. 7, 8 and 9 are elevations of three baiiles of a transverse baille assemblage, Fig. 7 being an end baille, Fig. 8 being an intermediate baille extending te one side of the assemblage, and Fig. 9 being an adjacent intermediate baille extending is a schematic view indicating the direction of travel of the fluid through the tubes.

In the present invention the shell, indicated generally by the reference numeral I, is formed of a plurality of detchably connected parts, namely an open ended drum 2, a hollow cover 3 closing one end of the drum, an open ended channel 4 extending from the other end of the drum and 4concentric therewith, and a ilat cover 5 closing the outer end of the channel.

The exchanger may be installed in a ver-tical or any other desired. position, but as it is particularly devised to serve as a transfer line exchanger, it is preferably disposed, as shown in Figs. 1 and 2, in a horizontal position and for convenience will be so described. To this end it is supported on two spaced cradles i5 secured to the bottom of the drum.

The baille system includes a main baille'I extending longitudinally oi the exchanger through the drum from the channel end thereof to or rsubstantially to the opposite end thereof and, in

the horizontal position of the exchanger, is preferably disposed, as shown, horizontally, extending from side to side of the drum to Which it is secured at its opposite longitudinal edges preferably by sealing it thereto, as by welding, throughout the entire length cf the baille.

A horizontal baille 8, which in effect is a continuation of the baille 'I, extends through the channel d from the baffle to the cover 5 and from side to side of the channel to which it is welded similar to the welding of the baffle I. The baille 'I divides the drum into an upper compartment 9 and a lower compartment I0, and the baille 8 divides the channel into an upper compartment II and a lower compartment I2, which compartments II and I2 are in effect respectively continuations of the compartments 9 and IB.

The baille system further comprises a unitary transverse baille assemblage, indicated generally by the reference numeral I3, disposed in compartment 9 and extending for a short distance into compartment I I, and another unitary transverse baille assemblage, indicated generally by the reference numeral I4, disposed in compartment I0 and extending for a short distance into cornpartrnent l2.

As these assemblages are similar in all respects a description of one, namely the upper assemlage I3 (shown particularly in Fig. 6), will sufoe. 1t rests upon the baille 1. The assemblage i3 includes longitudinally spaced transverse baliles, the end baffles or plates I5 to the other side of the assemblage; and Fig. 10 being thicker than the other transverse battles to add rigidity to the assemblage, and the thinner bailles being preferably equally spaced apart. The thinner bailles do not extend entirely across the iull width of the baille '1, alternate bailles, as the bailies it, extending from one longitudinal edge of the baille l toward, but not to, the other longitudinal edge, providing open spaces a, and the remaining intermediate bailles II, which are also alternate bailles, extending from the other longitudinal edge of the baille I toward, but not to, the opposite edge, providing other open spaces b.

Each baille i9 has a horizontal lower edge I8, supportedly engaging the baille 'I a vertical edge I9 extending upwardly from one end of the edge i8 providing, with the baille l and drum 2, one of the openings a, and a circular edge 29 connecting the opposite end of the edge I8 with the upper end of the edge i9, this edge 29 having the curvature of the drum and being disposed adjacent thereto. rThese bailles I6 are connected near the point of juncture between the edges I8 and 29 by a tie bolt 2I, the bailles having aligned orices to permit the passage therethrough of this bolt. Each baille Il has an edge I8', an edge I9 and an edge 29 similar to the edges I8, I9 and 29 of baille I6, except that the edge I9 is at the opposite end of the edge I9 and similar remarks apply thereto, except that the edge I9', with the baille 'I and drum 2, provides one of the openings b. These bailles I'I are connected by a tie bolt 22, similar to bailles I S.

The baffles I and II provide a winding or circuitous passageway for the passage of the iiuid through the upper compartment 9 which in the present instance, as will later appear, is from the upper compartment i I to the hollow cover.

The end plates I have relatively little bailling eiect and are therefore more strictly strengthening plates. They are similar to each other, each having a lower edge I S, a vertical edge I9", and a circular edge 29" corresponding respectively to the edges I9, I9 and 29 of baille I6. However plate i has another vertical edge I9" corresponding to the edge I9 of baille il. One of the plates I5 is centrally disposed in a transverse direction in compartment II with its edges I9 `and i9 spaced from the respective adjaf cent portions of the channel 4 to provide openings at each end of this plate I5. The channel 4 is concentric with and of a larger diameter than the drum I2 so that a space is provided between the edge 29 and the adjacent portion of the channel 9. Thus the fluid freely passes the plate i5 in channel 4 at the edges I9, I9' and 29". The edge 29" is of the same curvature as and in alignment with the edges 29 and Eil' in order that the assemblage maybe passed through the compartment 9 when desired, as will later more fully appear.

The other plate I5 is disposed in compartment 9 vat the end thereof adjacent the hollow cover. While the Iedge i8" may supportedly engage the baille] it is shown slightly spaced from the end of this baille. The edge 29 is adjacent the drum 2 but as this plate is disposed centrally similar to the plate I5 in the channel li, spaces are provided adjacent each edge I9" and I9"".

The plates I5 and bailles I5 and I7 are secured together by tie Ybolts 23, four being employed in the present instance, the plates and bailles being provided with aligned orifices to permit the passage therethrough of these bolts. The bolts 2i, 22 and 23 have mounted thereon tubular spacers 24 of suitable lengths to bear at their ends against the adjacent bailles and plates, and each bolt is provided at each end with a pair of nuts which, when tightened, firmly hold the parts tightly together to provide of the bailles, plates, bolts and spacers a unitary baille assemblage.

While the assemblages i3 and I9 are separate units, the assemblage Ill, as previously remarked, is similar to the assemblage I3 except it is supported upon the drum and, as is obvious, is inverted and consequently it is the curved edges of the baffles in the drum that are supportedly engaged by the drum. Further, while the baffles of the assemblage I4 are in vertical alignment with corresponding bailles of the assemblage I3, the corresponding bailles are reversed in direction providing a reversal in the positions oi the spaces a and b. It follows therefore that the assemhlage I4 provides a passage for the iluid similar to that of the assemblage I3 previously described, so that upon entering the hollow cover from the upper compartment, the iluid passes from the hollow cover through the winding or cirouitous passageway of the lower compartment I9 into compartment I2.

rEhe system of baffles aioredescribed causes a double flow in the exchanger of the fluid surrounding the tubes, the fluid passing first through the length of the top portion of the exchanger an-d then returning through the length of the bottom portion of the exchanger. However, if desired, the Acentral horizontal cailles 'I and S could be eliminated, making a single flow exchanger oi the apparatus. ln such a case, as is obvious, a single transverse baille assem- .blage of proper design would be employed, and

the fluid outlet would be at the opposite end of the exchanger from the fluid inlet, for instance in the wall of the drum adjacent the cover 3. However, the following description will be of a double-flow heat exchanger, by way of illustration, it being understood that the invention has application also to the singlenflow type of heat exchanger above mentioned.

The invention is not conned to any particular number of tubes, arrangement thereof, order of connecting, or to the direction of fluid flow through the tubes. However a feature of the invention resides in providing a group of tubes arranged in two banks or sets independently of each other except as to the return bend crossover coupling connecting a. tube of one set with a tube of the other set to provide for the continuous passage of fluid through all the tubes from the inlet end to the outlet end of the group, one set being disposed in the upper compartment 9 and the other set in the lower compartment I0. In the present instance however ten tubes are employed, ilve in each compartment, and in the preferred embodiment these are arranged and connected as clearly indicated in Fig. l0, the assumed direction of flow through the tubes being indicated in "Fig, 10 and also in Figs. 4 and 5 by the arrows. Therefore the following description will be coniined to the number of tubes, their arrangement, and the direction of ilow as indicated in Fig. 10. Return bends are employed for connecting the tubes, thus avoiding tube sheets which, as before stated, have been found unsatisfactory due to their tendency to distort and creep, especially when made relatively thick as is required in high temperature and pressure exchangers. Such tendency to distort and creep is due in part to the unequal temperatures between various portions of each tube sheet, which is a condition common in heat exchangersand further is due to unequal expansion and contraction between the various tubes secured to the tube sheets.

There is a set of` ve tubes 25, 23, 21, 23 and 29 in the lower compartment l0 and a similar set of ve tubes 25', 26', 21', 28 and 29" in the upper compartment 9. The adjacent tubes of each compartment are equally spaced in order that similar return bends 4may be employed throughout. Although the tubes 21-21 are shown as at slightly a greater space, requiring a larger return bend, they may be of an edual space requiring a return bend similar to the others. 'Ihe tubes 2.5, 26 and 21 are arranged in a horizontal row near the baille 1 and the tubes 28 and 29 are arranged in another horizontal row further from the baille 1, the tubes .of the rows being staggered. The tubes in comments, the bafes and plates being provided with .f

aligned orifices to permit this. The tubes extend for a short distance into the hollow cover to provide for their coupling with the return bends which are at this end, and, at their other ends, extend slightly beyond the plates.|5 disposed in the compartments and l2 to provide for their coupling with the return bends and outlet and inlet terminal couplings which are at this end, as will presently appear.

The return bends at one end of the apparatus are housed in the hollow cover and at the other end are housed in the channel. The return bends, with their associated parts. are preferably, as shown, separate from each other. all similar, and, as shown. are of a standard type requiring no threaded joints connecting the tubes with their bends, although other types may be employed.

The return bends 3|! for coupling the tubes are of U-shape'and each is connected to the tubes by two separate ring-shaped couplings 3|. A pair of spaced hollow branches 32 extend from one end of each coupling in a direction longitudinally of the axis of the coupling and this end of the coupling is provided with an outwardly flaring inner seat 33. The opposite end is provided with internal grooves 34, and is mounted on the end of a tube. the tube being rolled outwardly to expand it into the grooves 34, providing a sealed, locked joint permitting longitudiin longitudinal positioning of the couplings 3|.

'I'he return bend 39 is disposed within the aligned spaces with the ends of its legs extending each within the aring end of a coupling 3|, the ends of the legs being oppositely flaring providing a sealed joint when forced tightly into tbe coupling 3|, as will presently appear. The hollow branches 32 of each coupling 3| are provided with aligned orifices 36. A bar 31 is disposed across the 'space with its ends extending into the aligned orifices.

The bar is provided, at its portion spanning the space, with a threaded opening for a screw 38 which is inserted in the threaded opening after the bar is assembled and which bears at its end against a lug 39 formed on the return bend 39. Upon tightening the screws 38 the return bend, in an obvious manner, is forced tightly into engagement with the couplings 3|.

Fig. 5 shows the order of connecting the tubes by the return bends at the hollow cover end of the apparatus, the return bend at the left being the cross-over return bend connecting together one of the tubes in each drum compartment, namely the tubes 21 and 21. p

Fig. 4 shows the order of connecting the tubes by the return bends at the channel end of the apparatus. Here the two tubes at the right, (one in each drum compartment, namely tubes 25 and 25'), are not connected to a return bend but insteadeach of these tubes is connected to a terminal coupling 49, these couplings being disposed one in each of thecompartments Vand I2. 'Ihe coupling 4|! is connected to the tube in a manner similar to the manner of connecting a coupling 3| as aforedescribed, and a plug 4| for closing the coupling 49 is connected thereto similar to the manner of connecting a leg of the return bend as aforedescribed, as clearly shown in section in Fig. 1.

Each terminal coupling 4G is provided with a threaded lateral opening 42. The channel is provided with openings in which are welded flanged couplings 43, one in line with each of the threaded openings 42. A flanged fitting 44, threaded at the end opposite its flange. extends through each of the couplings 43 with a loose fit, providing thereby a limited degree of flexibility, especially as to the expansion and contraction of the terminal tubes. and is screwed tightly into the threaded opening 42 in alignment therewith, the flan-ge of the tting'M being provided with peripheral grooves 45 for the application of a wrench for turning the fitting 44. The ttings 44, due to their extending through the' exchanger side wall. do not interfere with removal of the cover 5 for inspection and cleaning of the parts.

The channel 4 is further provided with two other couplings 4.6 similar to the couplings 43, one provided for and opening into each of the compartments and I2.

Between the flanges of the couplings 43 and ttings 44 are sealing rings 41, grooves being formed in'these flanges for receiving the rings. Other sealing ring grooves are provided in the opposite faces of the of each of the ttings 44 and in the'outer faces of the flanges of the couplings 43, it being understood th'at the flanges of the couplings 43 and it are for se curing thereto', by means of bolts, the flanges of other pine couplings (not shown) similarly provided with sealing ring grooves, a sealing ring being disposed in each pair of these rrrooves and the flanges of the couplings 43 and 49 being provided with bolt holes (not shown).

"The cover 5 is provided with a groove 48 in which is seated the adiacent end of the baille 8, and an enlarged bar 4S, which is provided with a similar groove in which is seated the adjacent end of the baille 1, is disposed at opposite end ofthe baille 3 and secured thereto and to the channel as by welding (not shown).

The channel 4 and cover 5 are connected by a circular tongue and groove joint 553, the groove Y being in the cover and connecting with the K groove d8. A circular sealing gasket is disposed in the bottom of the tongue and groove joint and has a diametrically disposed cross rib seating in the bottom of the groove 48. A similar tongue and groove joint and gasket are provided between the channel Il and the drum 2, the groove being in the channel and connecting with the groove of bar Lig. A similar tongue and groove joint and gasket are provided between the hollow cover and the drum except that the gasket has no cross rib.

A groove l is formed in the outer face of the channel providing a circular shoulder 52 iiaring outwardly toward the opposite side of the groove. A clamping ring 53, which is made in two sections to enable it to be assembled, secures the cover 5 to the channel It has an interior flange 5d disposed in the groove 5I providing a shoulder 5.5 corresponding with and engaging the shoulder 52. The ring, at its opposite end, has another interior flange 5G extending over the peripheral margin of the outer face of the cover 5 and spaced therefrom sufficiently to permit the ring to be moved axially to clear its shoulder 55 from the shoulder 52 when assembling and disassembling, the groove El being of a suiiicient length to permit this. The flange 56 has a series of threaded orifices formed therein for screws 57 which, in an obvious manner, when tightened, rrnly hold and seal the cover 5 to the channel il and baille S. The drum and channel are secured together in a similar manner, the channel being provided with a flaring shoulder, and an outwardly extending fiange 58 being formed on the drum for receiving the ends of the screws. Thus the drum is firmly held and sealed to' the channel, and the baille 'i to the bar dil. The drum and hollow cover are secured together in a similar manner, the hollow cover being provided with the flaring shoulder, and an outwardly extending flange 59 being formed on the drum for receiving the ends of the screws. The tongue of the tongue and groove joints between the drum and channel, and between the drum and hollow cover, project respectively from the outer end faces of the flanges 53 and 59. Drain orifices provided with screw plugs 59 are provided in the bottom and top of the channel, and in the bottom and top of the hollow cover.

From the foregoing it will be see that the tubes are series connected, producing a continuous flow of fluid therethrough. The fluid enters the tube from the fitting 1M Connected thereto, this being considered the inlet fitting in the present set-up, as already stated. The fluid passes through' all the tubes in the lower compartment la in the manner indicated in Fig. 10, crosses over through the cross-over return bend disposed in the hollow cover from the tube 2l to the tube 27', and then passes through all the tubes in the upper compartment 9 in the manner indicated in Fig, 10, and from the tube 25 passes to the outlet fitting lil connected therewith. The uid surrounding the tubes exteriorly initially enters the compartment il through the coupling 43 connected therewith, this being considered the inlet coupling in the present setup, as already stated, and nally discharges from the compartment l2 through the outlet coupling 4S connected therewith. lThe fluid in the tubes is brought into most effective heat exchange relation with the fluid surrounding the tubes during the latter fiuids circuitous passage from the compartment li through the compartment S to the hollow cover and during its return circuitous passage from the hollow cover through the compartment if! to the compartment l2 The ttings lla, which extend through the side wall of the exchanger, provide the only connection that the group of tubes has with the shell. The tubes thereby are free to expand and con tract longitudinally responsive to temperature changes.

The chief advantage of the heat exchanger is this longitudinal freedomv of expansion and contraction of the pairs of tubes, thereby avoiding the setting up of strains and stresses so prevalent in constructions employing one or more tube sheets. This freedom of expansion and contraction is aided by providing sufcient tolerances between the transverse baffles and the shell and longitudinal baffle and also between the tubes and the transverse bailles, which tolerances permit slight lateral movement of the tubes, giving them sufficient flexibility, when it is required, to minimize the aforesaid strains and stresses when the tubes expand and contract. This is especially important for the reason that the various tubes will have diiferent temperatures due to the manner of heat exchange between the fluid in the tubes and that exterior thereto, which produces variable expansion. rfhis result is not obtainable where a tube sheet is employed at either or both ends of theV tubes.

It will be seen from the foregoing description that the parts of the exchanger are easily assembled and disassembled, facilitating cleaning, repairing and replacement of the parts,

Ey removal of the clamping rings, the various parts of the shell may be separated. By removal of the ttings ifi the entire tube group with both entire transverse baiie assemblages may be removed from the shell through the hollow cover end after the hollow cover has been removed, or, if desired, either set of tubes, with its transverse baiiie assemblage, may be removed from the shell in like manner after the cross-over return bend has been removed. The return bends are easily removed and the separate tubes may then be removed from their engaging transverse baffles and plates. Wherever there is a plurality of like parts they are made similar in all respects, thereby minimizing maintenance.

While there has been hereinbefore described an approved embodiment of this invention, it will be understood that many and various changes and modifications in form, arrangement of parts, and details of construction thereof may .be made without departing from the spirit of the invention and that all such changes and modifications as fall within the scope of the appended claim are contemplated as a part of this invention.

The invention claimed and desired to be secured by Letters Patent is:

In a heat exchanger, the combination of a horizontal cylindrical shell open at one end and having a horizontal baiiling and supporting partition providing an upper compartment and a lower compartment for series passes of fluid therethrough; a removable cover for said open end, said shell at its opposite end having two orices, one for each compartment, one serving as an inlet the other as an outlet for said fluid; a unitary structure in each compartment, each structure being removable as a unit through said open end and comprising a row of transverse, longitudinally spaced, baiiies provided with horizontal rows of orices, means rigidly securing the bafes together to form an assemblage thereof, and a bundle of tubes arranged in horizontal rows and supported by said baes, the tubes extending through said baiiie orices, and return bends interconnecting said tubes at adjacent ends to form a single passageway; a removable coupling combining said compartment passage- Ways together at the shell end adjacent said cover providing thereby a continuous passageway for series flow of fluid through the tubes thereof in heat exchange relation with said uid in said shell; and a removable coupling for each said compartment passageway connected to its opposite end and extending through said shell at its oriced end, said opposite end couplings serving one as an inlet and the other as an outlet for said continuous passageway, said upper unit being slidably supported on said partition and said lower unit being slidably supported on said shell.

MARTIN ETTINGTON.

JOHN MACRAE BARCLAY. 

